assclown

iTrader: (1)

so.... my a/c hasn't worked since the fall of last year (system was fully charged anyway). no big deal... winter is coming and i'll address the problem once it's needed. a week ago i'm driving to louisville to see my family and i notice a really bad noise when the engine is running. my brother and i put the car up on a lift and stick a screwdriver on the engine to find where the sound was coming from. turns out to be the bearing in the compressor. well gee sounds like we have two problems that can possibly be fixed by one solution. i was able to pickup a reman. compressor at advance auto parts for only $290 and brought it back to the dealership my brother works at and we installed it. lubed up all o-rings, charged the system, oiled the system. the bearing noise went away and the car was then driveable again. great.

well it's still not working. we troubleshot the problem down to the fact the compressor clutch was not engaging. we took a look at the wiring diagram and tested continuity from the fuse box, to the relay, to the compressor. the only place that didn't have continuity was the compressor. so we decided to test the compressor. we grabbed a long wire and hooked it up to the battery while the car was on. then we heard the clutch engage and blow cold air so now we know that the compressor just isn't getting power to it. i was thinking there is a short in the system between the compressor and the relay. my brother and i are far from electrical gurus so we decided it was best i take it to honda. here is their diagnosis.



does this sound right?

fsttyms1

Its very possible that is causing the problem. Dont let them bend you over for 350 for the mount. Thats expensive.

assclown

iTrader: (1)

haha thanks for the info. i figured the PCM is the same thing as the ECU right? i'm going to need to get a type-s ecu for my a2 engine anyway....


ignore that comment about the mount, i'll fix that on my own when i put the new engine in....

laziebun

i seriously doubt the PCM(ECM) has anything to do with the AC system. did you check the expansion valve that tells the compressor when to kick on or off?

TLer trash

Actually, it does. It supplies a ground to turn the ac clutch relay on.

assclown

iTrader: (1)

anyone have a spare ecu handy? haha so i can test?

friesm2000

iTrader: (4)

and it does that, so the ecu can at the same time kick the idle up to compensate for the increased load

friesm2000

iTrader: (4)

and first of all is the pcm, getting a command from the hvac unit for ac request, so it knows to turn it on (scan tool with live data works awesome for that)

friesm2000

iTrader: (4)

then second, is the relay flipping on or not (clicking and such) if not, then need to make sure it has power and ground to the coil

but if so then need to see if the contacts are letting power through (a jumper wire works awesome for that, just basically put it in for the relay, and does the a/c kick on???

friesm2000

iTrader: (4)

also remember the pcm does have other inputs before it will turn on the a/c

such as pressure switches on the a/c system, so those have to be happy before it will ever turn the a/c on (so scan tool with data is kinda critical)


but yeah i don't think the pcm is bad, they don't really just go bad so easily, especially like on hondas

assclown

iTrader: (1)

yeah, well when i turn the a/c on, the idle does go up.... but the clutch doesn't engage.

the relay is good, and we've even replaced it.

the only time the a/c kicks on is when the compressor is wired directly to the battery.

friesm2000

iTrader: (4)

then it does sound like the computer is demanding a/c

any fuses blown??? including the bigger ones????


as said try jumpering pass the relay, to to see if you can manually engage it that way (so remove the relay and stick some wire with spades in there) after checking to see if it has power of course

friesm2000

iTrader: (4)

anyways if that relay is also clicking, the pcm is NOT bad

basically the the coil it goes battery,wire,fuse,relay,wiring,coil, ground
and the pcm controls that relay

assclown

iTrader: (1)

fuses are good. we did do the relay jumping and nothing. i dunno

i gotta change the computer when i put my type s engine in anyway

eg5

iTrader: (4)

not doubting your skills, but are you sure you have the proper diagram/s or following the proper circuit?
did you check continuity from the compressor connector(engine harness side) to the clutch relay terminals at the underdash fuse box?
also carefully inspect those pins.
good luck

friesm2000

iTrader: (4)

yes check those pins

and also it sounds like you got a open in the wire and not a short, due to it not blowing fuses
so what is the voltage at the power input for the relay??? (remember there are two seperate fuses to that relay)
also when jumped what is the voltage at the coil connector, you might not have enough voltage there to even engage the coil (needs at least 10.5 or so) (might have corriosion in a connector or something)


and fyi i seriously doubt a computer will fix this issue, cause by the way it sound the pcm has absolutly no problem controlling that relay

totaledTL

Pressure-?

friesm2000

iTrader: (4)

pressure switch, to make sure the system is not undercharge (don't want to going being low on refrigerent)


then also there is a high side pressure switch which turns the system off, if the pressure gets too high, so you don't blow the safty vent disk, or overpressure anything else (safty disk goes at about 400-450 psi)

totaledTL

I know, I meant was the pressure switch checked, and/or is the pressure ok-?

assclown

iTrader: (1)

i know we used the right diagram, i have the service manual and we were looking at the HVAC wiring diagram for the "except type s models"

as far as voltage, i don't know. i'm not all that great with electrical stuff, i'm more mechanical. my brother was doing all that troubleshooting.

the charge is fine. we put in i think 1.6lbs in? i dunno we looked under the hood at the sticker and used the dealers charging system to do it. then we oiled the system up.

friesm2000

iTrader: (4)

lol

TLer trash

Assclown, the one thing fries mentioned that I'm not clear on; does the relay click? You mentioned bypassing it which isn't the same. Try pulling it while the engine is running, temp control full cold, fan speed full high, ac on. Gently sneak it back in and you should feel it click.
Are you checking the fuses with a test light or a voltmeter, and not just visually? Check fuse 58 30A underhood, fuse 14 7.5A passenger side dash, andfuse 3 7.5A driver side dash.

eg5

iTrader: (4)

agreed!
if i had to make a guess, id say there is an open between the ac compressor (engine harness side) and that clutch relay terminal.

assclown

iTrader: (1)

i'll have to check this out and report back. thanks for the info guys

laziebun

Check you low and high pressure switch.....that is what kick your compressor on also. I would do that before replacing your PCM

assclown

iTrader: (1)

i know my brother took some wire and put it in the relay spots and it blew a fuse. like i said, i've replaced the relay, and i just now pulled it out, while the car is on, running with a/c on and tried slowly popping it in, nothing happened.

i'm thinking that could be it too, i'm swapping the type s engine in anyway so i'm going to need a different engine wiring harness and hopefully the problem is there.

jdjohn84

Sorry to resurrect this thread, but I was having a similar problem today, and it turned out to be the connector from the compressor into the socket from the relay.

I replaced my compressor (salvage), all the hoses/lines, condenser, accum/recvr/drier myself, and then today had an evac/recharge done down at a full-service BP near my office. It was $80...not too bad. But when they were done, the compressor was not coming on, or I should say, the clutch was not engaging. They said it wasn't receiving power, and I told them I would try to fix that myself.

I took it home after work and hot-wired it to the battery; the clutch engaged, and I had cool air. I checked the fuse, it was fine, relay was getting juice, I jumped that to the relay output, but still no power to the compressor. There had to be something in the line between the relay and the compressor. When I replaced the compressor, I remember thinking how flimsy the connection was between the wire harness socket and the wire from the compressor. There is just that little slide connector on the end of the compressor wire, going into that big plug on the wiring harness, which comes from the relay.

Well, I had not pushed the wire connector far enough into the socket, so had no connection at all. You really have to push that wire connector as far back into the socket as possible. There is a rubber stopper around the compressor wire that slides up and down the wire, so after pushing the connector in as far as you can, you then slide the rubber stopper down the wire into the socket opening to keep it all together and seal the circuit from water or other nasties.

I'm a little disappointed in the shop, though. They should have found that. They said no power was getting to the compressor. Power was getting to the socket, just not to the compressor. They should have checked the socket and that connection.

friesm2000

iTrader: (4)

gotta make sure the connectors click in place (like the tab you push down to be able to pull it apart)

and as far as that shop goes, you never paid for there diagnosis, you just paid for the evacuate and refill part, and they did their said part of that
btw the power was still not getting to the compressor, no matter how close it was getting



also what did it say on the invoice, probably evac and recharge A/C system, with a note that they where not able to do it fully, since the compressor was not engaging (and btw you said you would try and fix it yourself, so you never even gave them a full chance at figuring it out)

jdjohn84

I'm probably missing a piece since this was from a salvage car, but there are not male and female connectors on mine that snap or click together. There is literally just an insulated wire with a tiny little metal slide connector on the end coming from the compressor. I had to shove that into the wiring harness plastic plug/socket connector, which seems to be oversized compared to that little wire from the compressor.

Regarding the shop, I guess I should have been more specific to say, "please check that power is getting to the socket where the compressor plugs in." If someone had asked me to check that 'power is getting to the compressor', I personally would have checked the socket that feeds power to the compressor, but maybe that's just me.

The other thing is that this is the second time I've had a problem of sloppy work on an a/c compressor with them. About a year ago, I took my previous car, an Infiniti I30t, to them to do an R&R on a compressor and charge the system. I provided the compressor, and they were to just do the labor. Again, when they were finished, the system held a charge, but no power to the compressor. Hmmm...I asked if they checked the fuses and relays. I didn't get a definitive answer on that, only that 'power is definitely not getting to the compressor.' I took it home, and the first thing I noticed is that the fuse was blown. I replaced the fuse, but it immediately blew again. Obviously there was a short somewhere. I was going to check continuity between the relay and the compressor, but when I looked at the hot wire on the compressor, I noticed that it was pinched by the flange of a mounting bolt, causing contact with the compressor housing (ground), and thus the short. I loosened the bolt, freed the wire, and everything worked. I took it back to them to show them, and needless to say, they were very embarrassed. They cleaned-up the exposed wire for free, and gave me credit towards some other work.

In the case of my TL, I replaced the compressor myself, so shame on me for not getting the connection right. But for them to say no power was getting there, and them to not even check that connector...that's bad.

I just don't think shops like to do electrical troubleshooting. They would rather remove and replace parts, do oil changes, etc. Good diagnostic work is hard to find.

friesm2000

iTrader: (4)

but diagnostic work is where you can really make the money though, if you are good at it, otherwise you can get your ass handed to you


and yeah if the car is a salvage title, i think you may have more issues then just that connector to worry about


but how i personally see it, is that you probably go looking for the cheapest price, and 95% of the time you get what you pay for


and for your connecter, simple it is probably not watertight, so corrosion got in there, and caused too much resistence that the compressor could not engage, which by moving it around, you got a good connection

assclown

iTrader: (1)

yeah john, sounds like you have same probs i have, but yours was fixable haha, when we removed my compressor, we noticed that the connection was ripped. it was no longer hooked to the clamps, so we took the clamps out and hardwired and soldered the connections. still no dice i guess i'll just have to go A/Cless till my engine swap

jdjohn84

Did you ever check your pressure switch? It was mentioned by others above, but I never saw that you checked it. It screws into the top of the receiver/dryer.

assclown

iTrader: (1)

no, i completely forgot about that one. how does one check that?

assclown

iTrader: (1)

we found the pressure switch. turned the car and a/c on, unplugged the pressure switch, the idle went down, plugged it back in, and the idle went back up. does that mean the pressure switch is good? i see the part is only $43 but do not wanna pay for a part and not be it. thanks!

friesm2000

iTrader: (4)

it seems that the ecu is seeing the pressure switch then, since it did change how it runs

friesm2000

iTrader: (4)

anyways do you have a multimeter/volt meter???

assclown

iTrader: (1)

eh, i believe he has one at the dealership he has access to. what would need to be checked?

friesm2000

iTrader: (4)

or even a test light might work too, but basically to see the available voltage at the relay, from each fuse (one for the winding, and the other one for the power to the compressor), then also to make sure the ecu is controling the ground for the relay, then also to see what the resistince might be to the compressor itself (no exact specs there, but i got an rough idea of what it should be though)

assclown

iTrader: (1)

so uh... i received my ecu yesterday and sent it off to richiev6 to have a key programmed to it, i was just curious since this ecu is a type s, and my car is not a type s, would it be ok to plug the new ecu in with my current setup (i'm sure i'd get a CEL, but honestly i don't care, we don't have inspections here) but would that possibly damage something? it's getting rough here without A/C

totaledTL

Uhm, why did you order one for an S if you don't have an S- was it a mistake?